Optical head capable of recording and reproducing information on any one of a plurality of kinds of optical information recording medium and optical information recording and reproducing apparatus using the same

An optical head for recording and reproducing information relative to an optical information recording medium having an arbitrary thickness among at least four kinds of thicknesses of a optical transmission layer including first and second different thicknesses and third and fourth different thicknesses, comprising:

• a first light source for emitting light of a first center wavelength, a second light source for emitting light of a second center wavelength and a third light source for emitting light of a third center wavelength;
• a first objective lens for irradiating light emitted from said first or second light source to said optical information recording medium and a second objective lens for irradiating light emitted from said first or third light source to said optical information recording medium;
• a photodetector for receiving light reflected from said optical information recording medium;
• an actuator for finely driving said first and second objective lenses;
• and
• a change mechanism for changing a combination of a light source to be used and an objective lens to be used,
• wherein said first, second and third light sources and said first and second objective lenses are combined in such a manner that said first light source and said first objective lens are used if said light transmission layer of said optical information recording medium has a first thickness, said first light source and said second objective lens are used if said light transmission layer has a second thickness, said second light source and said first objective lens are used if said light transmission layer has a third thickness, and said third light source and said second objective lens are used if said light transmission layer has a fourth thickness.